In most internal combustion engines, ambient air is mixed with fuel, and the air/fuel mixture is introduced into the working cylinder portion of the engine.
It is known to add a “velocity stack” or “air horn” to a carburetor or fuel injector. A “velocity stack” is often a cone-shaped device that is open to the outside and directs airflow to the air-fuel system. The velocity stack has a relatively large inlet opening and a relatively small outlet opening.
As described in U.S. Pat. No. 6,371,068, an adjustable vane may also be included in the air horn, in the air intake port of the cylinder head, or in both. In one known engine design, the vane in the air intake passageway of the cylinder head gradually twists so that the cross-sectional area of the air intake passageway gradually narrows toward the inlet port of the cylinder. Therefore, the primary effect of the vane is to change the direction of the airflow.
An embodiment of the invention provides an air intake system for an internal combustion engine that includes a modification in the path of the air flow leading to the engine.